This section explains how to configure Tomcat to use log4j rather than java.util.logging for all Tomcat’s internal logging.

Note: The steps described in this section are needed when you want to reconfigure Tomcat to use Apache log4j for its own logging. These steps are not needed if you just want to use log4j in your own web application. — In that case, just put log4j.jar and log4j.properties into WEB-INF/lib and WEB-INF/classes of your web application.

The following steps describe configuring log4j to output Tomcat’s internal logging.

1.Create a file called log4j.properties with the following content and save it into $CATALINA_BASE/lib

log4j.rootLogger = INFO, CATALINA

# Define all the appenders
log4j.appender.CATALINA = org.apache.log4j.DailyRollingFileAppender
log4j.appender.CATALINA.File = ${catalina.base}/logs/catalina
log4j.appender.CATALINA.Append = true
log4j.appender.CATALINA.Encoding = UTF-8
 

# Roll-over the log once per day
log4j.appender.CATALINA.DatePattern = '.'yyyy-MM-dd'.log'
log4j.appender.CATALINA.layout = org.apache.log4j.PatternLayout
log4j.appender.CATALINA.layout.ConversionPattern = %d [%t] %-5p %c- %m%n

log4j.appender.LOCALHOST = org.apache.log4j.DailyRollingFileAppender
log4j.appender.LOCALHOST.File = ${catalina.base}/logs/localhost
log4j.appender.LOCALHOST.Append = true
log4j.appender.LOCALHOST.Encoding = UTF-8
 

log4j.appender.LOCALHOST.DatePattern = '.'yyyy-MM-dd'.log'
log4j.appender.LOCALHOST.layout = org.apache.log4j.PatternLayout
log4j.appender.LOCALHOST.layout.ConversionPattern = %d [%t] %-5p %c- %m%n

log4j.appender.MANAGER = org.apache.log4j.DailyRollingFileAppender
log4j.appender.MANAGER.File = ${catalina.base}/logs/manager
log4j.appender.MANAGER.Append = true
log4j.appender.MANAGER.Encoding = UTF-8
log4j.appender.MANAGER.DatePattern = '.'yyyy-MM-dd'.log'
log4j.appender.MANAGER.layout = org.apache.log4j.PatternLayout
log4j.appender.MANAGER.layout.ConversionPattern = %d [%t] %-5p %c- %m%n

log4j.appender.HOST-MANAGER = org.apache.log4j.DailyRollingFileAppender
log4j.appender.HOST-MANAGER.File = ${catalina.base}/logs/host-manager
log4j.appender.HOST-MANAGER.Append = true
log4j.appender.HOST-MANAGER.Encoding = UTF-8
log4j.appender.HOST-MANAGER.DatePattern = '.'yyyy-MM-dd'.log'
log4j.appender.HOST-MANAGER.layout = org.apache.log4j.PatternLayout
log4j.appender.HOST-MANAGER.layout.ConversionPattern = %d [%t] %-5p %c- %m%n

log4j.appender.CONSOLE = org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.Encoding = UTF-8
log4j.appender.CONSOLE.layout = org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern = %d [%t] %-5p %c- %m%n

# Configure which loggers log to which appenders
log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost] = INFO, LOCALHOST
log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager] =\
  INFO, MANAGER
log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/host-manager] =\
  INFO, HOST-MANAGER

2.Download Log4J (Tomcat requires v1.2.x).

3.Download or build tomcat-juli.jar and tomcat-juli-adapters.jar that are available as an “extras” component for Tomcat. See Additional Components documentation for details.

This tomcat-juli.jar differs from the default one. It contains the full Apache Commons Logging implementation and thus is able to discover the presence of log4j and configure itself.

4.If you want to configure Tomcat to use log4j globally:

Put log4j.jar and tomcat-juli-adapters.jar from “extras” into $CATALINA_HOME/lib.
Replace $CATALINA_HOME/bin/tomcat-juli.jar with tomcat-juli.jar from “extras”.

5.If you are running Tomcat with separate $CATALINA_HOME and $CATALINA_BASE and want to configure to use log4j in a single $CATALINA_BASE only:

Create $CATALINA_BASE/bin and $CATALINA_BASE/lib directories if they do not exist.
Put log4j.jar and tomcat-juli-adapters.jar from "extras" into $CATALINA_BASE/lib
Put tomcat-juli.jar from "extras" as $CATALINA_BASE/bin/tomcat-juli.jar
If you are running with a security manager, you would need to edit the $CATALINA_BASE/conf/catalina.policy file to adjust it to using a different copy of tomcat-juli.jar.

6.Delete $CATALINA_BASE/conf/logging.properties to prevent java.util.logging generating zero length log files.

7.Start Tomcat